A vehicle differential carrier (commonly known merely as a “differential”) is a device employing differential gears therein, which typically are connected to its exterior by three shafts. An input shaft transmits torque and rotation into the differential gears from a vehicle engine. In turn, each of the other two shafts separately transmit a portion of the torque and rotation from the differential gears out to separate external wheels. Regarding the operation of the differential, when a vehicle is being driven straight the differential rotates with an axle, while side and pinion gears mate but do not rotate relative to each other. However, when the vehicle turns the differential still rotates but the side and pinion gears mate and slightly rotate so that one wheel can turn faster than the other.
Hence, the differential is needed because when a vehicle is turning, as it quite often does, the outside wheel makes a larger radius than the inside wheel. As a result, the outside wheel goes a farther distance, moves faster and turns more revolutions than the inside wheel. If, however, both wheels were on the same axle shaft, in this instance, one or both wheels would have to skid or slip to make a turn. Consequently, the function of the differential allows the wheels to turn at different speeds, but at equal torque.
In certain situations it is desirable to modify the action of the differential. For instance it may be desirable to lock the differential. Those skilled in the art will recognize that there are a number of different mechanisms to lock the relative rotation between a differential gear case and one of the output side gears. Control of the locking differential involves several actions. Engagement of the differential is controlled by an actuator. The actuator is in turn powered and signaled by the vehicle through a controller. In addition, it is beneficial to have a sensor that can relay information regarding the differential back to the controller. It would be beneficial to have a differential control system including an actuator, sensor and controller that was modular. Such a modular control system would facilitate manufacture and installation. It would also provide for feedback to the vehicle about the action and status of the differential. In addition, placement of the controller in close proximity to the differential allows for calibration to be done before installation of the differential. Further, specific placement of the controller can reduce noise (usually from electromagnetic currents) found in the system.